At the time, however, she was not only the largest ship that had ever been built, but was regarded as unsinkable, for she had sixteen watertight compartments. Even if two of these were flooded, she would still be able to float. The tragic sinking of this great liner will always be remembered, for she went down on her first voyage with heavy loss of life.

　　4. At the time, however, she was not only the largest ship that had ever been built, but was regarded as unsinkable, for she had sixteen watertight compartments.

　　当时，这艘轮船不仅是造船史上建造的最大的一艘船，而且也被认为是不会沉没的。当时，这艘轮船不仅是造船史上建造的最大的一艘船，而且也被认为是不会沉没的。因为船由16个密封舱组成，

　　语言点1:句子结构分析: however和but一般不会同时出现在一句话中，但本句例外，后半句其实是not only…but(also)…(不但…而且…)的结构。

　　语言点2:regard…as…的意思是“把…当作…”。

　　5.Even if two of these were flooded, she would still be able to float.

　　即使有两个舱进水，仍可漂浮的水面上。

　　语言点:句子机构分析:even if的意思是“即使”，引导让步状语从句。

　　6. The tragic sinking of this great liner will always be remembered, for she went down on her first voyage with heavy loss of life.

　　然而，这艘巨轮首航就下沉，造成大批人员死亡。人们将永远记着这艘巨轮的沉没惨剧。

　　语言点1:句子结构分析:for引导原因状语从句，交代沉船事件应该被铭记的原因。

　　语言点2:表示“沉没”的多种方法辨析:

　　Sink 下沉(动作)

　　Go down沉没(结果)

　　Drown 淹没(部分在水下)

　　Submerge 淹没(全部在水下)

　　Dive潜水(还能再主动出水)